Polyurethane copolymers have been widely used for numerous biomedical applications due to their excellent mechanical properties, biocompatibility, and hemocompatibility. In contrast to other materials used in vascular applications, such as polytetrafluoroethylene (PTFE) and polyethylene terephthalate (PET), polyurethane-based materials support the growth of endothelial cells and possess mechanical properties that match the native vasculature. (Tiwari A et al., Cardiovascular surgery (London, England) 10, 191 (2002).
Surface and/or bulk modification of polyurethane may be accomplished, such as by attaching biologically active species to reactive groups on the polyurethane molecule. Such modifications may be designed to control/mediate host wound healing responses. However, polyurethane is not inherently bioactive.
Hyaluronic acid (HA) and heparin are glycosaminoglycans (GAGs) found in all mammals. Hyaluronic acid is a unique and highly versatile biopolymer. Hyaluronic acid plays a vital role in embryonic development, extracellular matrix homeostasis, wound healing, and tissue regeneration. However, the exact mechanisms of hyaluronic acid's regulation of these events are unknown. The behavior and cell influences of hyaluronic acid are highly dependent upon its concentration and molecular weight. Biomaterials made from derivatized and cross-linked hyaluronic acid have been reported in the bioengineering community for applications such as orthopedic, cardiovascular, ophthalmology, dermatology, and general applications in tissue engineering, surgery and drug delivery. Hyaluronic acid is naturally derived and nonimmunogenic. It also has multiple sites for modification and inherent biological activities. (Leach J B et al., Encyclopedia of Biomaterials and Biomedical Engineering 2004, p. 779).